Atypical Ductal Hyperplasia

Atypical ductal hyperplasia occurs when you have abnormal cells in the milk ducts of your breast. These cells have a higher-than-normal chance of becoming cancerous. A breast biopsy diagnoses it. Your provider may recommend additional mammograms if you have atypical ductal hyperplasia.


Atypical Hyperplasia

What is atypical ductal hyperplasia?

Atypical ductal hyperplasia (ADH or atypia ductal hyperplasia) is when you have abnormal cells in the lining of the milk ducts in your breasts. Your milk ducts are small tubes that carry milk to your nipples. Typically, the cells in the lining of your milk duct appear lined up in two layers. With ADH, the cells are multi-layer and don’t line up. They appear disorganized or overgrown. The cells themselves are noncancerous (benign). But the cells share some features of ductal carcinoma in situ (DCIS), which is an early-stage breast (Stage 0) cancer. For that reason, ADH cells have a higher-than-average chance of changing into cancer.

Your healthcare provider diagnoses ADH with a breast biopsy. A biopsy involves your provider removing tissue from your breast and sending it to a lab for analysis. Treatment for ADH involves more regular breast cancer screenings so that if cancer does occur, it’s found as early as possible.

What is atypical hyperplasia?

Atypical hyperplasia is a general category that includes two types.

Hyperplasia is a term that describes abnormal cell growth. Sometimes, these cells appear normal under a microscope. But, when the cells are an irregular shape or size, a healthcare provider considers them atypical.

The two types are atypical ductal hyperplasia (ADH) and atypical lobular hyperplasia (ALH). ALH means that abnormal cells are in your breast lobule (the milk-making parts of your breast). ADH means abnormal cells are in the milk ducts (the tube that carries the milk to your nipple).


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What does having atypical ductal hyperplasia mean?

If your breast biopsy shows atypical ductal hyperplasia, it doesn’t mean that you have cancer. The cells are a marker for increased breast cancer risk. Studies have shown that people with either type of atypical hyperplasia may be up to four times more likely to get breast cancer compared to those who don’t.

A diagnosis of ADH usually means your healthcare provider will want you to have more breast cancer screenings such as mammograms, ultrasounds or breast MRIs (magnetic resonance imaging).

How common is atypical ductal hyperplasia?

A healthcare provider may find atypical ductal hyperplasia (ADH) in between 5% to 20% of breast biopsies. It’s not cancer but increases your risk of breast cancer up to 20% or 30% depending on the types of irregular cells your provider sees, as well as other risk factors like genetics or having a personal or family history of cancer.

Symptoms and Causes

What are the symptoms of atypical ductal hyperplasia?

There are sometimes no symptoms of ADH. It’s a condition your healthcare provider may find during an examination or breast cancer screening. Some people develop lumps, pain or irregular nipple discharge which can alert them that something is wrong with their breasts.


What causes atypical ductal hyperplasia?

Healthcare providers aren’t sure why the cells in your breast become irregular or why some people develop ADH. They do know that it increases your chance of developing breast cancer in the future. It’s best to talk to your healthcare provider to find out your risk for breast cancer.

What are the risk factors for atypical ductal hyperplasia?

Risk factors for ADH are similar to risk factors for breast cancer. But, many people develop breast cancer without any risk factors. These factors include:

  • Family history of breast cancer or genetic mutations.
  • Personal history of cancer.
  • Obesity.
  • Drinking alcoholic beverages or smoking cigarettes.

What are the complications of atypical ductal hyperplasia?

The main complication of ADH is that it increases your risk for breast cancer. It’s important to follow your provider’s treatment plan, which typically involves annual mammograms or other breast cancer screenings.

Diagnosis and Tests

How is atypical ductal hyperplasia diagnosed?

Your healthcare provider finds ADH during a needle biopsy while investigating abnormal findings on a mammogram or ultrasound. A needle biopsy is a procedure that allows your provider to draw cells from your breast tissue. They may also find ADH while determining the cause of symptoms like a breast lump or nipple discharge.

Upon examining the cells from your milk ducts, your provider will notice the cells are distorted or stacked in multiple layers.


Is atypical ductal hyperplasia stage 0 breast cancer?

No, ADH isn’t cancer. It only increases your risk for breast cancer because the changes in the cells resemble changes in cells that do become cancer.

How long does it take for atypical hyperplasia to turn into cancer?

ADH itself isn’t cancer. It increases your risk for breast cancer in the future. A person with an atypical ductal hyperplasia diagnosis may not get breast cancer. Additionally, your breast cancer risk increases over time:

  • After five years, about 7% of people with ADH will develop breast cancer.
  • After 10 years, about 13% of people with ADH will develop breast cancer.
  • After 25 years, about 30% of people with ADH will develop breast cancer.

Management and Treatment

How is atypical ductal hyperplasia treated?

The treatment for ADH is a surgical (excisional) biopsy to remove more of the tissue that contains atypical ductal hyperplasia, plus the area immediately surrounding it. Your provider will send this tissue to a lab to make sure there isn’t cancer present. If your biopsy comes back normal, no further treatment is necessary. Your provider usually recommends more breast cancer screenings. If your risk of cancer is very high, they may prescribe medications to reduce your risk.

It’s worth noting that treatment for ADH is personal and unique to your situation. Only you and your provider can make decisions on the best treatment for you.

Medications for people who have a high risk of breast cancer

People with atypical ductal hyperplasia may benefit from taking a five-year course of certain preventive medications. These medications block estrogen and help decrease the risk of estrogen receptor-positive invasive breast cancer. The effects can remain for up to 15 years after taking them.

If you haven’t reached menopause, your provider may recommend tamoxifen (Nolvadex®). If you’ve reached menopause, your provider may prescribe:

All of these medications have some side effects. But the number of serious side effects is very low.

You’ll need to have a detailed discussion with your healthcare provider to determine if these medications are right for you. Although not a routine recommendation, your provider may recommend a risk-reducing mastectomy (removal of your breasts) if your risk is especially high.

Follow-up care for ADH

Your healthcare will recommend annual breast cancer screenings and clinical breast exams (exams your provider performs) every six or 12 months. This ensures that if breast cancer were to develop, you can begin treatment as soon as possible. Treating breast cancer early leads to the best outcomes. Talk to your provider about what they recommend. You may qualify for an annual breast MRI based on your risk factors.

Should atypical ductal hyperplasia be removed?

Most healthcare providers perform surgery to remove the entire area of tissue where the atypical cells were found. Providers find precancerous or cancerous cells in up to 20% of surgeries for ADH.

Care at Cleveland Clinic


Can I prevent atypical ductal hyperplasia?

It’s helpful to become familiar with your own breast tissue so you can identify changes. Learning how to perform self-breast checks at home is the best way to do this.

While you can’t prevent ADH, you can take steps to reduce your risk. Some of these steps include:

  • Maintain a healthy weight.
  • Exercise daily.
  • Limit or avoid beverages containing alcohol.
  • Avoid smoking cigarettes and using tobacco products. (If you smoke or use tobacco, your provider can give you resources to help you quit.)

Outlook / Prognosis

What is the risk of breast cancer with atypical ductal hyperplasia?

Your risk for breast cancer increases up to four times compared to someone without atypical hyperplasia. Other factors are involved in determining your overall risk. Be sure to discuss your risk with your healthcare provider.

Living With

How do you manage atypical ductal hyperplasia?

Follow your healthcare provider’s instructions for follow-up care. This involves attending all breast cancer screenings and making healthy lifestyle choices to reduce your risk. Lifestyle choices could include maintaining a healthy weight, exercising regularly and avoiding beverages containing alcohol.

ADH increases your risk for breast cancer but doesn’t necessarily mean you’ll get breast cancer. Talk to your healthcare provider about your risk of developing cancer in the future. Be sure to ask any questions you have about treatment.

When should I see my healthcare provider?

Alerting your healthcare provider to any changes in the look or feel of your breast is important. Knowing what to look for is key to taking control of your breast health. Perform self-breast exams and attend annual examinations with your provider so they can find any changes early.

Contact your provider if you notice:

  • A lump or another change in how your breasts feel.
  • Irregular or bloody nipple discharge.
  • Dimpling, redness or swelling of the skin of your breasts.
  • Changes in the direction of your nipple such as your nipple turning inward.

What questions should I ask my healthcare provider?

If you receive an atypical ductal hyperplasia diagnosis, you may want to ask your provider:

  • What do my test results mean?
  • Do I need surgery?
  • What symptoms should I look for that mean I have breast cancer?
  • What are my chances of developing breast cancer?
  • Do I need more breast cancer screenings like mammograms?
  • What else do I need to do to manage ADH?
  • Should I consider genetic counseling?

A note from Cleveland Clinic

Having ADH can be stressful and cause worry since it increases your risk for breast cancer. Remember, an ADH diagnosis doesn’t mean you have breast cancer. It means your provider needs to watch you more closely. Be sure to follow your healthcare provider’s advice, including going to all your follow-up appointments and breast cancer screenings, and maintaining a healthy lifestyle. Talk to your provider about your overall risk for cancer and don’t be afraid to share your feelings with friends, family or others who can support you.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 11/16/2023.

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